The present invention relates generally to a dynamic behavior control apparatus for an automotive vehicle, and more specifically, to a method and apparatus for controlling the lateral dynamics of the vehicle by controlling the front and/or rear wheel steer angle for the vehicle.
Dynamic control systems for automotive vehicles have recently begun to be offered on various products. Antilock braking systems (ABS) and traction control (TC) control tire slip ratios. More advanced dynamic control systems typically control the side slip angle and yaw response of the vehicle by controlling the tractive forces and/or braking torque at the various wheels of the vehicle. Side slip and yaw control systems typically compare the desired direction, yaw response, and lateral acceleration of the vehicle based upon the steering wheel angle, speed, and the direction of travel to an ideal (stable) vehicle model. By regulating the amount of braking torque and tractive friction at each corner of the vehicle, the desired path of travel and yaw rate may be maintained.
The yaw control systems mentioned above thus do not control the lateral or yaw response by controlling steering of the front wheels directly. Because of this, front independent control of steady state and dynamic response occurs. However, by having closed loop control over front or rear wheel steer angle, some tradeoffs between the vehicle steady state lateral dynamics and stability and the vehicle transient lateral dynamic response may be achieved.
It would therefore be desirable to provide a closed-loop control system that allows the transient lateral response and the steady state lateral gain and stability to be maintained, optimized, controlled, and/or tailored.